EPICHLOROHYDRIN

Epichlorohydrin is a federal hazardous air pollutant and was identified as a toxic air contaminant in April 1993 under AB 2728.

CAS Registry Number: 106-89-8

Molecular Formula: C3H5ClO

Description

Epichlorohydrin is a colorless, mobile, liquid and has an irritating chloroform-like odor. It is soluble in benzene, miscible with alcohol, ether, chloroform, trichloroethylene, and carbon tetrachloride, and immiscible with petroleum hydrocarbons. It is not soluble in water (Howard, 1990).

Physical Properties of Epichlorohydrin

Molecular Weight92.53
Boiling Point116.5 oC
Melting Point-48.0 oC
Flash point, open cup40 oC (105 oF)
Water solubility65.8 at 20 oC
Vapor Density3.29 (air=1)
Vapor Pressure10 mm Hg at 16.6 oC
Density/Specific Gravity1.1812 at 20/4 oC (water=1)
Log/Octanol Water Partition Coefficient0.26
Conversion Factor1 ppm = 3.78 mg/m3

(Howard, 1990; Merck, 1989; Sax, 1989; U.S. EPA, 1994a)

SOURCES AND EMISSIONS

A. Sources

Epichlorohydrin is used as a chemical intermediate, coating, solvent, surface active agent, and a stabilizer in insecticides. It is also used in epoxy resins, textile treatment, and in elastomer manufacturing (HSDB, 1991).

Epichlorohydrin was registered for use as a pesticide; however as of December 3, 1986, it is no longer registered for pesticidal use in California (DPR, 1996).

The primary stationary sources that have reported emissions of epichlorohydrin in California are cement manufacturing, ship and boat building, and transportation equipment (ARB, 1997b).

B. Emissions

The total emissions of epichlorohydrin from stationary sources in California are estimated to be at least 8,600 pounds per year, based on data reported under the Air Toxics "Hot Spots" Program (AB 2588) (ARB 1997b).

C. Natural Occurrence

No information about the natural occurrence of epichlorohydrin was found in the readily-available literature.

AMBIENT CONCENTRATIONS

No Air Resources Board data exist for ambient measurements of epichlorohydrin.

INDOOR SOURCES AND CONCENTRATIONS

Epichlorohydrin is a solvent used in some architectural coatings; emission data from such products are not available (Hodgson and Wooley, 1991). Few measurements have been made of indoor concentrations of epichlorohydrin. Samples for this volatile organic compound were collected in a study of six public buildings located in the east coast (Sheldon et al., 1988b). None of the samples had measurable levels of epichlorohydrin. The quantifiable limits varied from 2.6 to 5.2 nanograms per cubic meter, depending on sample size.

ATMOSPHERIC PERSISTENCE

The dominant atmospheric loss process for epichlorohydrin is expected to be the gas phase reaction with the hydroxyl (OH) radical. Based on this reaction, the atmospheric half-life and lifetime of epichlorohydrin is estimated to be 20 and 30 days, respectively (Atkinson, 1995).

AB 2588 RISK ASSESSMENT INFORMATION

The Office of Environmental Health Hazard Assessment reviews risk assessments submitted under the Air Toxics "Hot Spots" Program (AB 2588). Of the risk assessments reviewed as of April 1996, epichlorohydrin contributed to the total cancer risk in 14 of the approximately 550 risk assessments reporting a total cancer risk equal to or greater than 1 in 1 million. Epichlorohydrin also contributed to the total cancer risk in 4 of the approximately 130 risk assessments reporting a total cancer risk equal to or greater than 10 in 1 million (OEHHA, 1996a).

For non-cancer health effects, epichlorohydrin contributed to the total hazard index in 3 of the approximately 89 risk assessments reporting a total chronic hazard index greater than 1 (OEHHA, 1996b).

HEALTH EFFECTS

Probable routes of human exposure to epichlorohydrin are inhalation and dermal contact.

Non-Cancer: Epichlorohydrin is a respiratory tract and eye irritant. Acute exposure to epichlorohydrin can cause severe respiratory effects. Symptoms may range from eye, nose and throat irritation to nausea, vomiting, cough, chemical pneumonitis, and pulmonary edema. Renal lesions may also be observed in humans. Chronic exposure to epichlorohydrin in humans has been associated with high levels of respiratory tract illness and hematological effects (decreased hemoglobin concentration and decreased erythrocyte and leukocyte counts) (U.S. EPA, 1994).

A chronic non-cancer Reference Exposure Level (REL) of 0.3 micrograms per cubic meter (g/m3) is listed for epichlorohydrin in the California Air Pollution Control Officers Association Air Toxics "Hot Spots" Program, Revised 1992 Risk Assessment Guidelines. The toxicological endpoint considered for chronic toxicity is the kidney (CAPCOA, 1993). The United States Environmental Protection Agency (U.S. EPA) has established a Reference Concentration (RfC) of 1 g/m3 based on changes in the nasal turbinates in rats and mice. The U.S. EPA estimates that inhalation of this concentration or less, over an entire lifetime, would not likely result in the occurrence of chronic, non-cancer effects. The U.S. EPA has calculated a provisional oral Reference Dose (RfD) for epichlorohydrin of 0.002 milligrams per kilogram per day. The U.S. EPA estimates that consumption of this dose or less, over an entire lifetime, would not likely result in the occurrence of chronic non-cancer effects (U.S. EPA, 1994a).

No adverse reproductive effects in humans were reported in available studies (U.S. EPA, 1994a). There are three studies in rats by oral or inhalation routes which have found reduced fertility after exposure to epichlorohydrin (U.S. EPA, 1984c; U.S. EPA, 1995b). The State of California has determined under Proposition 65 that epichlorohydrin is a male reproductive toxicant (CCR, 1996).

Cancer: An increased incidence of lung cancer in workers exposed to epichlorohydrin was reported in epidemiological studies; however, the results were not statistically significant. The U.S. EPA has classified epichlorohydrin in Group B2: Probable human carcinogen. The U.S. EPA calculated an inhalation unit risk estimate of 1.2 x 10-6 (microgram per cubic meter)-1. The U.S. EPA estimates that if an individual were to breathe air containing epichlorohydrin at 0.8 g/m3 over an entire lifetime, that person would theoretically have no more than a 1 in 1 million increased chance of developing cancer (U.S. EPA, 1994a). The International Agency for Research on Cancer has classified epichlorohydrin in Group 2A: Probable human carcinogen based on inadequate evidence in humans and sufficient evidence in animals (IARC, 1987a).

The State of California has determined under Proposition 65 that epichlorohydrin is a carcinogen (CCR, 1996). The inhalation potency factor that has been used as a basis for regulatory action in California is 2.3 x 10-5 (microgram per cubic meter)-1 (OEHHA, 1994). In other words, the potential excess cancer risk for a person exposed over a lifetime to 1 g/m3 of epichlorohydrin is estimated to be no greater than 23 in 1 million. The oral potency factor that has been used as a basis for regulatory action in California is 8.0 x 10-2 (milligram per kilogram per day)-1 (OEHHA, 1994).